Rebuilding rear calipers.

[Simmo]

Hi & good evening. I am currently in the process of overhauling the brakes on the S4 and have successfully rebuilt the front calipers and refitted them to the car with new braided hoses. I have now moved onto the rears and they've been stripped, cleaned and painted. I have today tried to fit the new pistons and seals / dust covers..... but to no avail. Does anyone on here got any tips on how to fit said dust covers? I've tried fitting them first and then inserting the piston through them, I have also tried fitting the dust cover to the piston and then tried to fit the piston/cover combo together... all advice greatly received. Thank you in advance.

[danielmo]

When I did these for the rear brakes on my formula car (same caliper), they were a royal pain. I think it took me at least 6 tries on each one. I had brake grease all over me and the dust covers, which didn't make it any easier. I think I ended up using (carefully) a small screw driver to cajole the seal into the piston and caliper. It's been a couple years since I did it, so I may have not remember all that I did to make it work. I did finally get them on.

[mbell]

I had similar pain. In the end the method that worked was fitting the dust seal to the caliper and pushed the piston through the dust cover and into the bore.

It is tricky to get the piston through the dust seal but easier than getting the dust seal seated in it's groove on the caliper with the piston in place.

[lotocone]

I had similar pain. In the end the method that worked was fitting the dust seal to the caliper and pushed the piston through the dust cover and into the bore.

It is tricky to get the piston through the dust seal but easier than getting the dust seal seated in it's groove on the caliper with the piston in place.

I did about the same thing, as I remember from a few years ago. I did split the calipers in two which helped with access and used a new small seal between the two halves. To get the dust seal in the caliper and piston grooves I used a very small screwdriver (jeweler's screwdriver) to carefully work the rubber into the grooves. That part was done in good sunlight to make sure the seal was seated properly. .

[gus]

It has been a veeery long time, but dust seal in the caliper and piston into dust seal is the only workable way. Yeah, probably a small screwdriver after getting the piston crooked to start into the seal, then leaning and prying the seal around the piston.

Now it is pooooossible to slip the seal onto the piston and then blindly get the seal into the caliper, but i dunno.....

[Simmo]

Well I've done it! Really easy when I approached it with a fresh set of eyes. As mentioned fitting the dust cover into the caliper first and then pushing the piston through the cover and into the caliper. So long as the caliper is spotlessly clean and the dust cover is seated correctly in the groove (I ran my finger round the inside of it once fitted to ensure it was squarely seated) with a little bit if rubber grease the piston goes in surprisingly easily. It's then just a matter of getting the cover sat in the groove on the piston properly. So thank you to all that replied and I hope this may help someone else in the future.